Field of the Invention
This invention relates to a grateless furnace of the type, hereinafter referred to as of the type described, having a combustion chamber in the bottom of which solid fuel forms a bed (herein referred to as a fire bed) in which, in use, combustion takes place, the furnace including means to direct air (herein referred to as primary air) through the bed to assist in combustion.
One example of such a furnace is described in detail in U.K. patent specification No 641024.
Grateless furnaces of the type described have the advantage that the temperature of fine fuel particles and ashes which accumulate at the bottom of the fire bed is maintained sufficiently high to permit of combustion of the fuel particles and to cause the ashes to melt or fuse to form slag.
However, in known furnaces of the type described it has been necessary to frequently rake out the slag and other non-combustibles (hereinafter referred to as slag) so that they do not reduce the efficiency of the furnace and to make space in the combustion chamber for new fuel to be introduced.
It is an object of the present invention to provide a new or improved grateless furnace of the type described which overcomes or reduces this problem.